The invention relates to a photocoupler comprising a light emitting element and a light receiving element, the light emitting element having a first and a second electrode in electrical contact with a first and a second contact pin, respectively, by means of which the light receiving element is fixed in position, the light receiving element having a third and a fourth electrode in electrical contact with a third and a fourth contact pin, respectively, by means of which the light receiving element is fixed in position, while the light emitting element and the light receiving element are situated opposite one another and enveloped in a first solid and transparent layer, surrounded at least in part by a second solid layer provided in such a manner as to reflect the light.
Such a device is known from French Patent Application FR-2 262 407 filed on Feb. 22th 1974. In this document, the second resin is rendered reflective by the fact that its refractive index is lower than that of the first resin. It is usual nowadays to use a resin filled with, for example, TiO.sub.2 ("white resin") for the second layer, which resin of itself has reflective properties.
The manufacturing processes of photocouplers generally comprise as their last step the injection molding of an opaque housing followed by its polymerization through baking.